TLR4 is activated by LPS and this recognition activates the Src family kinases, Src, Fyn and Yes, which in turn contribute to tyrosine phosphorylation of Zonula adherens proteins to open the endothelial paracellular pathway.

TLR4 transfection of eukaryotic host cells using bacterial vectors, or bactofection, was shown to reduce E. coli colonization in the kidney and the bladder in an animal model of urinary tract infection. (Demonstrated in murine model)

TLR4 is involved in the transmission of ER stress from tumour cells to macrophages, promoting a pro-inflammatory program in the tumour microenvironment, thus facilitating tumour progression. (Demonstrated in murine model)

TLR4 deficient murine macrophages results in the complete abrogation of TNF-alpha production during Leishmania panamensis infection. The endosomal TLR4 plays a crucial role in the activation of host macrophages and controlling the early stages of parasitic infection. (Demonstrated in murine model)

TLR4 and HSPD1 mediate myocardial ischemia-activated innate immune signalling, which plays an important role in mediating apoptosis and inflammation during ischemia/reperfusion (I/R). (Demonstrated in murine model)

H. pylori infection induces the expression and activation of components of NLRP3 inflammasomes in neutrophils and this activation is independent of a functional type IV secretion system, TLR2 and TLR4.

[Mus musculus] Tlr4 transfection of eukaryotic host cells using bacterial vectors, or bactofection, was shown to reduce E. coli colonization in the kidney and the bladder in an animal model of urinary tract infection.

[Mus musculus] Tlr4 is involved in the transmission of ER stress from tumour cells to macrophages, promoting a pro-inflammatory program in the tumour microenvironment, thus facilitating tumour progression.

[Mus musculus] Tlr4 deficient murine macrophages results in the complete abrogation of TNF-alpha production during Leishmania panamensis infection. The endosomal Tlr4 plays a cruical role in the activation of host macrophages and controlling the early stages of parasitic infection.

[Mus musculus] Itgam (Cd11b) fine tunes the balance between adaptive and innate immune responses initiated by LPS by modulating the trafficking and signalling functions of Tlr4 in a cell-type-specific manner.

[Mus musculus] Nod1 and Nod2 synergize with Tlr4 in dendritic cells to increase IL12 production and enhance invariant natural killer T (iNKT) cell activation, and are important regulators of the IFN gamma response by iNKT cells during S. typhimurium and L. monocytogenes infections.

[Mus musculus] Ticam1 but not Myd88 signalling is critical for the Trl4 protective adjuvant effect in neonates; where Ticam1(-/-) but not Myd88(-/-) neonates are highly susceptible to Escherichia coli peritonitis and bacteremia.

[Mus musculus] Peli3 is involved in endotoxin tolerance and functions as a negative regulator of Tlr2/4 signalling.

Entrez Gene

Summary

The protein encoded by this gene is a member of the Toll-like receptor (TLR) family which plays a fundamental role in pathogen recognition and activation of innate immunity. TLRs are highly conserved from Drosophila to humans and share structural and functional similarities. They recognize pathogen-associated molecular patterns that are expressed on infectious agents, and mediate the production of cytokines necessary for the development of effective immunity. The various TLRs exhibit different patterns of expression. This receptor has been implicated in signal transduction events induced by lipopolysaccharide (LPS) found in most gram-negative bacteria. Mutations in this gene have been associated with differences in LPS responsiveness. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jan 2012]

InnateDB is being developed jointly by the Brinkman Laboratory (Simon Fraser University, British Columbia, Canada),
the Hancock Laboratory (University of British Columbia, Vancouver, British Columbia)
and the Lynn EMBL Australia Group (South Australian Health & Medical Research Institute and Flinders University, Adelaide, Australia).

Funding is currently provided by Allergen and EMBL Australia. Previous funding has been provided by Genome Canada, the Foundation for the National Institutes of Health
through the Grand Challenges in Global Health initiative and by Teagasc. InnateDB curated interactions are licensed under the Design Science License. All other data is licensed under the terms of the originating database.
Contact: innatedb-mail@sfu.ca